[volt-nuts] volt-nuts Digest, Vol 55, Issue 6
Michael Hong
mikeyahee at yahoo.com
Sat Mar 8 23:55:42 EST 2014
Bill:
Thank you for the detailed info.
Since my stroke and depression at my early 50's, my language ability
changed a lot. Writing, talking and typing, too. But getting better. So lots of people ask
me the same question. I live in Cypress, Orange County, California. Within a few miles of me, there a lots of high tech companies , like Boeing.
The seller's DMM needs to be calibrated or better yet to be repaired.
I have many 6 1/2 digit and 7 1/2 digit DMMs. Two of them NIST caled by locals. All measure the 732A high and out of ranges. But always 10V and 1V are within 5ppm and 1.018V is within 30ppm of 10V and 5V.
Look at the seller DMM reading 10V : +40ppm 1V: -20ppm and 1.018V range show -50ppm.
To make more accurate assessment of this 732A's output, It needs to be compared to another Zener or accurate 3458A.
Once it is found out of cal ranges, I will return it or sell it to whomever wants it at my cost and understand no battery and has to be fixed.
I talked to most if not all cal labs around me. Most of them are poor. They are closing the business or are struggling to maintain their business as is. I heard two labs are selling their equipments. They can't afford to own and calibrated 732A/B, ESI SR104, L&N Thomas one. They can't afford Agilent's Loveland 3458A calibration. Most of the lab owner can't afford one employee. They are doing the lab as part time job.
I think the closest and affordable JJA services are Fluke(WA) and Agilent(CO). All others are government or military labs. Sandra is very expensive by hearsay.
Is there any 'nut' 100 miles from me with reasonably accurate 3458A or 732A/B? I like to take my either 3457A, Gell-Lab SVR-T, or 732A to you to compare with yours. All I need is within +-5ppm from JJA. New 34461 can be a good comparable too. Any 6 1/2 or 7 1/2 digits calibrated by either Agilent or Fluke will be good, too.
Until then everything is wild guess, I think, sorry. Anybody willing to give me the help with these equipments send me an email. I will be deeply appreciated.
Thank you all.
Best Regards,
On Saturday, March 8, 2014 7:05 PM, "volt-nuts-request at febo.com" <volt-nuts-request at febo.com> wrote:
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Today's Topics:
1. Re: A Fluke 732A: Return it or keep it? (Bill Gold)
2. Re: A Fluke 732A (Richard Moore)
3. Re: Economical Standard Calibration (Dallas Smith)
4. Re: A Fluke 732A: Return it or keep it? (Tom Knox)
5. Re: Economical Standard Calibration (Bob Albert)
----------------------------------------------------------------------
Message: 1
Date: Sat, 8 Mar 2014 16:21:36 -0800
From: "Bill Gold" <wpgold3637 at att.net>
To: "Discussion of precise voltage measurement" <volt-nuts at febo.com>
Subject: Re: [volt-nuts] A Fluke 732A: Return it or keep it?
Message-ID: <006a01cf3b2d$88a6e5c0$b7f95c47 at home>
Content-Type: text/plain; charset="iso-8859-1"
Michael,
Just a side note here on adjusting the 3 calibration pots inside the front
panel of the 732A
Fluke did supply an adjustment tool with each 732A but I don't know exactly
who made it or what model number. I use a General Cement ( GC ) model 8276
adjustment tool, the end with the blade recessed, to do the job. Sometimes
it takes a little fiddling and patience to get the adjustment tool to engage
the slot in the pot, but it can be done and without any danger of shorting
something out.
http://www.alliedelec.com/search/productdetail.aspx?SKU=70159521
360 uvolts ( 36 ppm ) above 10 volts seems more than a little high for one
of these units. The worst I have seen over 6 units is around 120 uvolts (
12 ppm ) out of spec, but I was able to bring it in by changing the jumpers
on the A7 board. It is conceivable that someone totally screwed up the last
calibration. You would need to take off the top cover, the top guard cover,
remove the top foam piece and take a look at the jumpers on the A7 board.
The one thing I can't remember right now is if shorting the resistors R12
through R17 on the A5 board, by adding or removing jumpers on the A7 board
lowers or raises the output voltage at 10 volts. But in the manual I did
find an addendum to paragraph 4-38 which says.
"Cutting a jumper increases the 732A 10 V output the amount labeled above
the jumper. Likewise, completing a jumper decreases the output the amount
of the jumper label".
So that should help you once you view the jumpers on the A7 board. I do
know that you can add or remove multiple jumpers on the A7 board so the
total range of the change in the 10 V output can be around 750 uvolts ( 75
ppm ). If you see many jumpers on the A7 board this would mean that someone
tried to lower the output voltage and that the reference could not be
adjusted properly to exactly 10 V. In other words if you see no jumpers on
the A7 board then you could possibly bring the output to exactly 10 V from
it's present ( presumed ) 36 ppm too high. You really need a "standard" 10
volts before you do this. But since the seller's DVM is reading 40 ppm too
high and your 3457A is reading 36 ppm too high then the output of the 732A
is probably also high.
What part of the country are you located in? Maybe one of the many "Volt
Nuts" lives close to you can give you an idea of what 10 Volts really is.
Also I have seen batteries that are so old and messed up that the "Charging"
light will never come on. The internal resistance is so high that the
charging circuit simply doesn't work. Your thermistor value and stability
seems very good so it looks like the oven temperature control circuits are
working correctly.
I hope the above helps you in determining if you keep the unit or send it
back.
Bill
----- Original Message -----
From: "J. L. Trantham" <jltran at att.net>
To: "'Michael Hong'" <mikeyahee at yahoo.com>; "'Discussion of precise voltage
measurement'" <volt-nuts at febo.com>
Sent: Friday, March 07, 2014 5:57 PM
Subject: Re: [volt-nuts] A Fluke 732A: Return it or keep it?
Michael,
The schematic of the A5 Reference PCB Assembly shows the calibration
adjustments and the drawing of that assembly shows the location of the
adjustments. They are deep inside the unit. You'll need a small flat
bladed tool, a flashlight, and probably a magnifier. I used a length of 12
ga. copper wire with one end flattened to make a screwdriver.
Good luck.
Joe
-----Original Message-----
From: volt-nuts-bounces at febo.com [mailto:volt-nuts-bounces at febo.com] On
Behalf Of Michael Hong
Sent: Friday, March 07, 2014 6:19 PM
To: volt-nuts at febo.com
Subject: [volt-nuts] A Fluke 732A: Return it or keep it?
(3)
Front panel calibration hole
I put a thin flat blade driver into the holes. I couldn't feel anything
until 4 1/4" inside where I felt something but not the potentiometer.
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Message: 2
Date: Sat, 08 Mar 2014 17:17:53 -0800
From: Richard Moore <richiem5683 at gmail.com>
To: volt-nuts at febo.com
Subject: Re: [volt-nuts] A Fluke 732A
Message-ID: <531BC141.50406 at gmail.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Back to a few of the original issues. A big questionh would be just how
accurate the average volt nut needs the 732A to be? I once owned two
732A, one working normally, and kept hot 24/7, and one that needed some
work with the charging circuits and new batteries. My 3458A being newly
cal'd at Agilent in Colorado Springs, I matched the two 732As to the
3458A, then powered off the one with problems, worked on it off and on
over several weeks, then powered it back up. What I found was that the
one I worked on (after 48 hours warm-up) was within 0.2ppm of the hot
one and the 3458A. Over the next year, the drift got a little larger
among the three, but not by much -- a spread of about another 0.2ppm if
I remember right.
That's when I decided that since I wasn't going to try to be a standards
lab, shipping a 732A cold for cal was much easier and effective than
trying to do it hot, and I live about 30 air miles from Fluke in Everett.
Can you live with 1ppm uncertainty in your 732A? Some here obviously
can't, but I think many of us can and would be happy with that level of
accuracy -- certainly good enough to cal the various 6-1/2 digit meters
around, including the 3457 mentioned originally. And given my experience
of 732A stability, especially the good old ones that come on ebay and
the like, that 1ppm uncertainty is also a good check on the state of cal
of even the 8-1/2 digit boxes, which despite their resolution, are not
spec'd long-term for even 1ppm at 10V.
Best,
Dick Moore
------------------------------
Message: 3
Date: Sat, 8 Mar 2014 20:26:23 -0500
From: Dallas Smith <dosmith at outlook.com>
To: Discussion of precise voltage measurement <volt-nuts at febo.com>
Subject: Re: [volt-nuts] Economical Standard Calibration
Message-ID: <BLU173-W61A13B82F3EDB51DFC82FBC750 at phx.gbl>
Content-Type: text/plain; charset="Windows-1252"
I'm in west Michigan, Holland. As far as accuracy the manual states ?10ppm for 30 day or ?30ppm per year for the 10v output .
I need it to calibrate my (modified with reference oven) EDC (Electronic Development Corp.) model 520a. Which I calibrate my Fluke 510a with a Fluke 720 voltage divider. I use the 510a to calibrate DB voltage for my audio test equipment. I also have a Fluke 8505, Fluke 8800 and Data Precision Model 2500.
So if I can achieve ?50ppm per year this would be sufficient, but better would be nice since they may not be calibrated every year.
I?m just a hobbies audio engineer that designs audiophile equipment and other interesting projects not related. So sending it to fluke is not economical for me.
Since Joe suspended operations for his SVR-T with low cost calibration. I purchased one and put it in a 35?C oven and it seems to outperform the Fluke 731b as compared to my 8505 for drift. I will have three 10 volt references in my lab to track uncertainty.
So are there any calibration labs that will calibrate my 731a and my home brew reference?s?
> Date: Sat, 8 Mar 2014 16:00:41 -0700
> From: nova at npgcable.com
> To: volt-nuts at febo.com
> Subject: Re: [volt-nuts] Economical Standard Calibration
>
> Dallas,
>
> How accurately do you need the 731B set?
>
> Where are you located? I am in Flagstaff, Arizona
>
> I have four 731s, and I know how to calibrate them.
>
> I also have a 3458A and a Fluke 7001 that goes to Fluke for calibration soon. I
> do not know the turnaround time.
>
> Joe
>
>
> On 3/8/2014 3:13 PM, Dallas Smith wrote:
> > Good point, not a meter a Fluke 731b transfer standard. no access to local labs.
> >
> > On 3/8/2014 4:54 PM, Dr. David Kirkby wrote:
> >> On 8 March 2014 21:44, Dallas Smith <dosmith at outlook.com> wrote:
> >>> Hi nuts,
> >>> This is my first post. The knowledge from contributors is amazing.
> >>>
> >>> Was wondering where one could economically get our_voltage standards
> >>> calibrated_
> >>> to some traceable standard since Joe Gellar suspended operations for his
> >>> SVR-T?
> >>>
> >>> voltagestandard.com doesn't sell a 10v references and two of his 5v
> >>> Vref5-002 are costly.
> >>>
> >>> Dallas
> >> It would be worth stating what meter you have. Clearly what is going
> >> to be useful for a 3.5 digit meter, will not be for an 8.5 digit one.
> >>
> >> Dave
> >> _______________________________________________
> >
> _______________________________________________
> volt-nuts mailing list -- volt-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> and follow the instructions there.
------------------------------
Message: 4
Date: Sat, 8 Mar 2014 19:01:26 -0600
From: Tom Knox <actast at hotmail.com>
To: Discussion of precise voltage measurement <volt-nuts at febo.com>
Subject: Re: [volt-nuts] A Fluke 732A: Return it or keep it?
Message-ID: <COL130-W650C73854F0640689BDFCADF750 at phx.gbl>
Content-Type: text/plain; charset="iso-8859-1"
I think everyone missed my point, Replace the current battery with ANY other type battery that is not destroyed by deep cyclng. Perhaps Ni-Mh would be better. Ni-Mh also has a very consistent output voltage (Low voltage drop) until nearly discharged. Also a quick Google search found a wealth of information on shipping Li-Ion and it appears the 732A batteries are right on the edge of no shipping restriction.
Thomas Knox
> Date: Sat, 8 Mar 2014 23:56:19 +0000
> From: vnuts at toneh.demon.co.uk
> To: volt-nuts at febo.com
> Subject: Re: [volt-nuts] A Fluke 732A: Return it or keep it?
>
> Unfortunately the hazards are indeed very real. The regulations were
> almost certainly introduced because a UPS cargo plane crashed in Dubai
> in 2010, killing both crew, as a result of a catastrophic fire in the
> cargo of 80,000 to 90,000 lithium batteries.
>
> http://online.wsj.com/news/articles/SB10001424127887324110404578625801602671408
>
> And surprise, surprise:
>
> 'It added that shippers of some of the lithium battery cargo loaded onto
> the plane in Hong Kong "did not properly declare these shipments" and
> did not provide battery test reports recommended under U.N. aviation
> guidelines.'
>
> (Which may be of interest to those buying those AD584LH voltage
> reference modules containing a lithium battery from Ebay).
>
> And from
>
> http://www.flyingmag.com/news/ups-747-crash-highlights-lithium-battery-danger
>
> In a *recent report issued by the FAA in conjunction with Transport
> Canada* <http://www.fire.tc.faa.gov/pdf/TC-13-2.pdf>, the agencies
> predicted there will be an average of six cargo plane crashes between
> now and 2021, with four of them likely to be caused by battery fires.
> Read more at
> http://www.flyingmag.com/news/ups-747-crash-highlights-lithium-battery-danger#1FZYPdiLXxLz0Fby.99
> 'In a recent report issued by the FAA in conjunction with Transport
> Canada, the agencies predicted there will be an average of six cargo
> plane crashes between now and 2021, with four of them likely to be
> caused by battery fires.'
>
> Tony H
>
> On 08/03/2014 22:32, Robert Atkinson wrote:
> > Hi David,
> > Our posts crossed. Note that the laptop battery has been independently safety tested. Or at least it should have been. Also you are no longer allowed to put batteries in you checked airline luggage, only carry-on and there are limits on the Lithium content (now expressed in WH to make it easier). This is pure safety addressing a very real hazard. The krytron restriction is ITAR (google it) as they are used to fire slapper detonators in nuclear weapons (that probably got a ping on a monitoring service;-).
> >
> > Robert G8RPI.
> >
> >
> >
> >
> > ________________________________
> > From: David C. Partridge<david.partridge at perdrix.co.uk>
> > To: 'Discussion of precise voltage measurement'<volt-nuts at febo.com>
> > Sent: Saturday, 8 March 2014, 22:04
> > Subject: Re: [volt-nuts] A Fluke 732A: Return it or keep it?
> >
> >
> > You can ship a Li-Ion or Li-Po battery inside a laptop no problem, but not
> > on its own.
> >
> > No it doesn't make sense except to the postal/shipping/airline safety types.
> > Probably the same logic that applies to exporting krytrons (even though Made
> > in China applies to these too).anymore).
> >
> > Regards,
> > David Partridge
> > -----Original Message-----
> > From:volt-nuts-bounces at febo.com [mailto:volt-nuts-bounces at febo.com] On
> > Behalf Of Chuck Harris
> >
> > Sent: 08 March 2014 21:36
> > To: Discussion of precise voltage measurement
> > Subject: Re: [volt-nuts] A Fluke 732A: Return it or keep it?
> >
> > Surely that isn't true... otherwise laptop computers and cell phones
> > wouldn't be allowed on board passenger aircraft. A laptop computer's
> > battery would greatly exceed the power in the original 732A battery pack.
> >
> > -Chuck Harris
> >
> > _______________________________________________
> > volt-nuts mailing list --volt-nuts at febo.com
> > To unsubscribe, go tohttps://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> > and follow the instructions there.
> > _______________________________________________
> > volt-nuts mailing list --volt-nuts at febo.com
> > To unsubscribe, go tohttps://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> > and follow the instructions there.
> >
>
> _______________________________________________
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------------------------------
Message: 5
Date: Sat, 8 Mar 2014 19:05:14 -0800 (PST)
From: Bob Albert <bob91343 at yahoo.com>
To: Discussion of precise voltage measurement <volt-nuts at febo.com>
Subject: Re: [volt-nuts] Economical Standard Calibration
Message-ID:
<1394334314.67677.YahooMailNeo at web122606.mail.ne1.yahoo.com>
Content-Type: text/plain; charset=utf-8
I have five AD587 switch selected, powered by a wall wart.? They seem to be very good, but of course not in the league of the units discussed here.
In any case, they are 10V and all within about a millivolt.? If I average them I should get a statistically valid accuracy improvement, neglecting any systematic errors in their manufacture.
While watching the display on my HP 3456A I begin to realize that my need for 'exact' voltage isn't really so great.? Certainly what I have is more accurate than anything I will ever really need.? But it's fun to see the variation and watch the drift and compare my other high class voltmeters.? The 3456A manual says to wait an hour for it to warm up and that seems reasonable; nearly all the drift is gone by about 45 minutes.
Bob
On Saturday, March 8, 2014 5:34 PM, Dallas Smith <dosmith at outlook.com> wrote:
I'm in west Michigan, Holland. As far as accuracy the manual states? ?10ppm for 30 day or ?30ppm per year for the 10v output .
I need it to calibrate my (modified with reference oven)? EDC (Electronic Development Corp.) model 520a. Which I calibrate my Fluke 510a with a Fluke 720 voltage divider. I use the 510a to calibrate DB voltage for my audio test equipment. I also have a Fluke 8505, Fluke 8800 and Data Precision Model 2500.
So if I can achieve ?50ppm per year this would be sufficient, but better would be nice since they may not be calibrated every year.
I?m just a hobbies audio engineer that designs audiophile equipment and other interesting projects not related. So sending it to fluke is not economical for me.
Since Joe suspended? operations for his SVR-T with low cost calibration. I purchased one and put it in a 35?C oven and it seems to outperform the Fluke 731b as compared to my 8505 for drift. I will have three 10 volt references in my lab to track uncertainty.
So are there any calibration labs that will calibrate my 731a and my home brew reference?s?
> Date: Sat, 8 Mar 2014 16:00:41 -0700
> From: nova at npgcable.com
> To: volt-nuts at febo.com
> Subject: Re: [volt-nuts] Economical Standard Calibration
>
> Dallas,
>
> How accurately do you need the 731B set?
>
> Where are you located? I am in Flagstaff, Arizona
>
> I have four 731s, and I know how to calibrate them.
>
> I also have a 3458A and a Fluke 7001 that goes to Fluke for calibration soon. I
> do not know the turnaround time.
>
> Joe
>
>
> On 3/8/2014 3:13 PM, Dallas Smith wrote:
> > Good point, not a meter a Fluke 731b transfer standard. no access to local labs.
> >
> > On 3/8/2014 4:54 PM, Dr. David Kirkby wrote:
> >> On 8 March 2014 21:44, Dallas Smith <dosmith at outlook.com> wrote:
> >>> Hi nuts,
> >>> This is my first post. The knowledge from contributors is amazing.
> >>>
> >>> Was wondering where one could economically get our_voltage standards
> >>> calibrated_
> >>> to some traceable standard since Joe Gellar suspended operations for his
> >>> SVR-T?
> >>>
> >>> voltagestandard.com doesn't sell a 10v references and two of his 5v
> >>> Vref5-002 are costly.
> >>>
> >>> Dallas
> >> It would be worth stating what meter you have. Clearly what is going
> >> to be useful for a 3.5 digit meter, will not be for an 8.5 digit one.
> >>
> >> Dave
> >> _______________________________________________
> >
> _______________________________________________
> volt-nuts mailing list -- volt-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> and follow the instructions there.
??? ??? ??? ? ??? ??? ?
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